§1. Design principles
Generated from
docs/LANGUAGE.md§1. This is the normative specification; for a guided tour see the Language and Neurosymbolic sections.
Eight principles, each grounded in the corpus. Every construct in §5 must satisfy all of them.
- Probabilistic under the hood, deterministic at the boundary. Every construct has a nonempty deterministic guarantee column — no Sema construct is purely statistical. The guarantee map (05 §5) is generated by one rule: a generative result’s guarantee level equals the strongest sound check applied to it (verifier-inheritance, 05 §4.4).
- Enforced, never advisory. SymbolicAI’s
@contractrecords failure but never blocks execution — DbC as advice (01 §6); Claude Code documents that natural-language rules are “context, not enforced configuration” (03). In Sema, a value that fails its contract is typed as failed and cannot flow into non-handling code. A library cannot make validation non-bypassable; a compiler can. That is the reason Sema is a language. - Honest grading. Statistical verdicts are typed as statistical and carry their evidence
(score, judge identity, threshold, calibration set, α). A fuzzy bool silently cast to
bool— SymbolicAI’sProbabilisticBooleanModeword-matching (01 §3) — is a language-level defect class Sema eliminates by construction. - Pinned judges.
semantics(),~=, and every model-evaluated predicate denote a pinned judge (model hash + prompt + threshold + calibration set), making evaluation total and reproducible; judge-vs-intent agreement is a separate, quantified statistical question (05 §1.4). Changing a judge is a semver-major change to program semantics. - The model proposes, the toolchain disposes. Every LLM-produced artifact (test, patch, translation, output) passes deterministic execution filters before it enters the build or the dataflow — Meta’s Assured-LLMSE discipline, which is what made 73% human acceptance possible (09 §2.5). LLM self-assessment is banned from any acceptance path (10).
- Accrete determinism. Statistical and adversarial findings are distilled into permanent deterministic artifacts (counterexamples, killed mutants, regression properties); a Sema codebase’s verification substrate hardens monotonically (09 §7.2).
- Familiar surface, honest divergence. Pythonic syntax, explicitly not a Python superset — Mojo’s landing position, never its launch position (12 §1). LLM authors are first-class: the grammar ships as a constrained-decoding artifact and the spec as the generator corpus (12 §6).
- No super-Turing claims. Sema + computable model oracles is exactly Turing-equivalent; the oracle framing buys a query/trust/substitutability boundary, not power (05 §1.2, arXiv:2406.12213).